Automatic clamping mechanism for molds



July 5, 1932.

L. EGGERT 1,865,434

AUTOMATIC CLAMPING MECHANISM FOR MOLDS Filed Aug. 50. 1929 Patented July 5, 1932 UNITED s rE s PATENT! on on. 1

i V LEWIS neemvr, or? TOLEDO, onro AUTOMATIC icLAMrING MECHANISM FOR. MOLDS App1ica.tion filed August so, 1929. Serial a... 389,393.

My invention relates to improvements in molding machines, i v I The'object of my invention is to provide an improved fluid operated clamping mechanism for holding the flask or moldsecurely in place on the molding machine while the mold is being made. 7 i

A further object is to provide an improved fluid operated Clamping mechanism which will automatically swing into and out of clamping position upon theapplicationof fluid pressure for controlling the mechanism. Other objects of my invention will appear hereinafter. a 1

Fig. 1 is an elevation, partly in section, of a molding machine having clampingmechanism embodying'm'y invention;

Fig. 2- is a fragentary top plan view of the clamping mechanism; and

Fig. 3 is a detail,-partly in section, of the clamping mechanism. i E a Y The molding machine shown. in'the drawing is known as a jolting or jarring mechanism upon which a pattern and flask is placed and by means of which the mold is rapidly jolted or jarredup and'down for the purpose OfPflCklIlg or'ramming themoldin'g. sand firmly and quickly around the pattern. This mechanism comprisesgenerally a vertically disposed cylinderfin the center ofjthe frame 2, inwhich cylindera plunger or piston is adapted to operate; The plunger has a table 3 at its upper end onwhich the pattern 4 is placed. This pattern is mounted on asuitable mold board or' pattern plate 5 which, is

placed on the table 3 of the jolting mechanism. The pattern plate is substantiallycirculan in form and extends laterally from the patternsufliciently toform a ledge or flange for the flask 6. The flask 6 has ears ;7'on its periphery which engages with short upstandingpins 8 on the edge of the pattern plate for the purpose oflining the flask with the pattern, but the .pins andears 7 andS permit 'the flask to be vertically rmoved with respect to the pattern plate to separate the mold from the pattern, as indicated in dottedfli'nes' in Fig.1; The flask is circular in form and surrounds the pattern to provide a space for the y molding sand 9. It has a plurality of radial Bo ribs 10 supporting at its center a gate por- .tion 11; V Beneath the jolting machine table 3 is a pair of strippers 12 which are disposed at di- 7 ametric'ally opposite points. These strippers have'stripper pins 13 whichextend vertically upward in suitable bearings 14 and through the table 3 and pattern plate '5. Their upper ends engage the under edge of the flask. Each Stripper has two pins spaced apart and 1m secured at their lower ends to ears 15 on the stripper casings. The strippers comprise cylinders 16 in which the plungers 17 operate vertically, the casing 12 being in the form of a cylindrical housing carried-at the up- 05 per end of the plunger and extending downwardly outside of the cylinder to protect the parts against-the entrance of sand and dirt. The plungers 17 are hollow and containfoil or other suitable operating fluid 18. The lower ends of the hollow plungers have ports 19 which communicate with the cylinder chamber below the piston and the upper ends of the hollow plungers have ports 20 connected'by the pipesQl which extendto a 15 suitable source of control air pressure for the purpose of operating the strippers.

When a mold has been completed, as shown in Fig. 1 the mold is withdrawn from the pattern by elevating it vertioally with respect to'thepattern. Pressure is admitted to the cylinder plungers which force the oilthrough the ports 19 into-the cylinder chambers below the plungers, thus forcingthe'plungers upwardly. The mold may then be removed from the'stripper pins by any suitable han dling mechanism. The flask for the next mold is placed on the elevated stripper pins, withthe'pins and ears? and 8 in alignment, andthe flask is'lowered to the mold plate 5 by releasing the pressure in the strippers and allowing the weight of the flask to force the plungers downwardly, returning the oil to the hollow plungers through the ports 19.

It is necessary to clamp the flask firmly on the pattern plate while the jolting mechanism is in operation and for this purpose I provide clamping mechanism which automatically operates to clamp or release the flask as the case may be. In the present structure two of these clamps are disposed diametrically oppositely and mounted at the edge of the pattern plate. The clamps comprise cylinders 25 in which pistons 26 operate. Both ends of the cylinders are closed to provide chambers above andbelow the pistons. The upper chambers have ports 27 and the lower chambers have ports "28 both of which are connected by the pipes 29 with a suitable source of compressed air. When air is admitted to the lower chambers the pistons will be forced upward and when admitted. to the upper chambers the pistons will be forced downwardly. The length of stroke of the pistons corresponds to the vertical movement of the flask. Each piston rod 30 has an enlarged end 31 which is guided in a suitable bearing 32 formed by the reduced upper end of the cylinder structure. On the upper end of the piston rodthe clamping arm 33 is mounted. These clamping armsextend laterally to engage the upper edge of the flask. The clamping arms have integral cup shaped'members 34 which extend down over the bearing portions 32, forminghousings which protect the bearing against the entrance of sand and dirt, These cup shaped members haveinsta-nding pins-35 which engagecam slots 36 inthe bearing portions 32 so as to impart a rotary movement to the clamping arms33 as they are moved vertically .by the pistons. The purpose of this pinand cam. slot arrangement is to swing the clamping arms clear of the flask, as shown in Fig. 2, when the clamps move upwardly to release the flask. Conversely, when the clamps move downwardly the clamps are swung into position to engage the edge of the flask beforeclamping pressure is applied to the flask. The lower end portions 37 of the cam slots are disposed vertically so as to hold the clamping arms against rotation while the clamping arms are in engagement with the flask. i r Thus itwilljbe seen that the clamping arms are automatically rotated or swung into and out of position in the movement of the clamp vertically :to clamp or release-the flask and this rotary movement, due to the vertical portions 37 of the slots, occurs injtime to position the arrows before clamping pressure is applied onto remove the arms after-clamping pressure is released as the case may be. 7

@I am aware, that changesin the constructionrand arrangement of parts may be made without departing from the spirit and scope of the invention and I reserve the right to make such changes as come within the scope of the appended claims.

I claim:

1. In a structure of the class described the combination of two relatively movable members for clamping a mold flask between them, and means for horizontally swinging one of said members into and out of position with respect to the flask when said member is moved vertically relative to the flask.

2. In a molding machine the combination of a pattern plate, a clamping member movable relatively to the pattern plate for clamping a mold flask between said member and the pattern plate, means for horizontally swinging said clamping member to and from its clamping position with respect to the flask when said clamping member is moved vertically relative to the flask, and means for holding said clamping member against horizontal movement during a portion of the vertical movement.

3-. The combination 0]": a pattern plate, a stationary cylinder mounted on said pattern plate, a piston movable vertically in said cylinder, a clamping arm operated by said piston to clamp a flask between said clamping arm and the pattern plate, and means for horizontally rotating the arm into and out of position with respect to the flask.

4. The combination of a pattern plate, a stationary cylinder mounted on said pattern plate, a piston movable in said cylinder, a clamping arm operated by said piston to clamp a flask between said clamping arm and the pattern plate, and a pin and cam slot connection between the stationary cylinder and the clamping arm arranged to rotate the clamping member to and from position relatively to the flask.

p 5. The combination of a pattern plate, and fluid operatedclamping mechanism for clamping a mold flask on said pattern plate, 5

and comprising a cylinder mounted on said pattern plate, a piston movable in said cylinder and adapted to be fluid operated, a piston rod connected to said pistons, a clamping arm on said piston rod for engagement with the mold flask, and a pin and cam slot connection between the arm and said cylinder for rotating the clamping arm into and out of position witi respect to the flask as the piston is operate I 6. The combination of a mold jolting mechanism on which a mold is mounted and means for clamping the mold on said jolting mechanism comprising a cylinder and'a piston reciprocable therein, aclamping member for the mold vertically movable by said piston towards and from the jolting mechanism, and means operable by the movement of said pistion vfor horizontally swinging the clamping arm into and out of position relative to the mold.

7 In a clamping mechanism for molding machines the combination of mold jolting mechanism and a pneumatically operated a clamp mounted thereon for clamping a mold on said jolting mechanism and having a clamping member for engaging the mold, and means for horizontally rotating the clamping member towards and away from the mold as the clamp is operated to clamp-or release the mold.

LEWIS EGGERT. 

